Effect of χ-alumina addition on H 2 S oxidation properties of pure and modified γ-alumina

Yashnik, S. A.; Kuznetsov, V. Ya.; Ismagilov, Z. R.

doi:10.1016/s1872-2067(18)63016-5

Cited by 14 publications

(9 citation statements)

References 73 publications

(144 reference statements)

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“…The total amount of acid centers, and their distribution, related to ammonia desorption, are presented in Table 2 for the studied range, calculated as the area under the concentration-time curve of the TPD profiles, according to regions. The Lewis acid sites of alumina are coordinated with NH3, due to the electron deficiency of trivalent aluminum atoms, presenting a maximum centered at 548 K [57]. Furthermore, the peak centered at 1073 K (strong acid region) was the most significant in the catalysts studied and corresponds with Brönsted acid sites where the hydrogen atoms may act as proton donor [58].…”

Section: Nh3 and Co2-tpd Studiesmentioning

confidence: 94%

“…According to their nature, acid centers of different strength and adsorbed NH 3 reaction towards NO x formation, define three regions: up to 523 K, weak acid sites (Lewis nature); from 523 to 673 K, middle acid sites (Lewis); and strong acid sites (Brönsted nature) from 673 K [41,49,57]. Depending on the metal modifying the alumina support of the catalyst and according to the metal active phase, the NH 3 -TPD profiles will be different.…”

Section: Nh 3 and Co 2 -Tpd Studiesmentioning

confidence: 99%

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Effect of the Addition of Alkaline Earth and Lanthanide Metals for the Modification of the Alumina Support in Ni and Ru Catalysts in CO2 Methanation

et al. 2021

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In order to reduce greenhouse gas emissions, which are reaching alarming levels in the atmosphere, capture, recovery, and transformation of carbon dioxide emitted to methane is considered a potentially profitable process. This transformation, known as methanation, is a catalytic reaction that mainly uses catalysts based on noble metals such as Ru and, although with less efficiency, on transition metals such as Ni. In order to improve the efficiency of these conventional catalysts, the effect of adding alkaline earth metals (Ba, Ca, or Mg at 10 wt%) and lanthanides (La or Ce at 14 wt%) to nickel (13 wt%), ruthenium (1 wt%), or both-based catalysts has been studied at temperatures between 498 and 773 K and 10 bar pressure. The deactivation resistance in presence of H2S was also monitored. The incorporation of La into the catalyst produces interactions between active metal Ni, Ru, or Ru-Ni and the alumina support, as determined by the characterization. This fact results in an improvement in the catalytic activity of the 13Ni/Al2O3 catalyst, which achieves a methane yield of 82% at 680 K for 13Ni/14La-Al2O3, in addition to an increase in H2S deactivation resistance. Furthermore, 89% was achieved for 1Ru-13Ni/14La-Al2O3 at 651 K, but it showed to be more vulnerable to H2S presence.

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Section: Nh3 and Co2-tpd Studiesmentioning

confidence: 94%

Section: Nh 3 and Co 2 -Tpd Studiesmentioning

confidence: 99%

Effect of the Addition of Alkaline Earth and Lanthanide Metals for the Modification of the Alumina Support in Ni and Ru Catalysts in CO2 Methanation

et al. 2021

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“…Alumina provides excellent impact resistance, chemical resistance, abrasion resistance, and high-temperature properties and this material is cheaper than other ceramic materials for this purpose. Alumina can be found in several different phases: alpha (α), beta (β), gamma (γ), eta (η), qi (χ), delta (δ) and cap (κ) alumina [21][22][23][24][25]. The α-alumina particles look like white powder, have a small active surface, are more resistant to high temperatures, and have very good physical and mechanical properties.…”

Section: Ceramic Fibers For Ballisticsmentioning

confidence: 99%

Ballistic Composites, the Present and the Future

Stupar¹

2022

Smart and Advanced Ceramic Materials and Applications

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In recent decades, the expansion of arms development has initiated the need to increase the protection of people and vehicles from pistol and rifle ammunition. Modern ceramic and ceramic-based materials are lightweight and durable and provide a sufficient level of protection against the penetration and impact of ammunition, which can protect the vital organs of the person. Modern tendencies require the addition of armor to vehicles, which reduces the necessity of excessive bulk steel usage and eliminates large and heavy mass weight amounts. By replacing the armored steel with new ballistic materials, a higher level of ballistic protection could be achieved, as well as reduction of weight, which both allows better mobility and increases the ability of installment of additional battle fighting equipment. Modern ceramic materials used in the production of armor are made by sintering the ceramic powder under certain conditions in a suitable molding tool. The chapter will cover the short material requirements, and material responses to ballistic impact, production methods, and applications. Also, the chapter will include the usage of ceramic fibers, alumina, silicon and boron carbide, titanium diboride, and ballistic materials that consist of a ceramic face bonded to a reinforced plastic laminate or metallic backplate.

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“…The catalytic activity of γ‐Al 2 O 3 , (γ + χ) ‐Al 2 O 3 , and α‐Al 2 O 3 , which were synthesized by the hydrocarbon‐ammonia molding method, in H 2 S oxidation was provided by Yashnik et al It was reported that ~40% H 2 S conversion was obtained with γ‐Al 2 O 3 at 250°C. They suggested that H 2 S was adsorbed on weak Lewis acid sites.…”

Section: Introductionmentioning

confidence: 99%

“…They reported that V 2 O 5 was the most active catalyst and alumina was among the lowest catalytic activity in H 2 S selective oxidation among the 21 metal oxides studied. [4] The catalytic activity of γ-Al 2 O 3 , (γ + χ) -Al 2 O 3 , and α-Al 2 O 3 , which were synthesized by the hydrocarbon-ammonia molding method, in H 2 S oxidation was provided by Yashnik et al [31] It was reported that~40% H 2 S conversion was obtained with γ-Al 2 O 3 at 250 C. They suggested that H 2 S was adsorbed on weak Lewis acid sites.…”

Section: Introductionmentioning

confidence: 99%

A new sol‐gel route alumina for selective oxidation of H₂S to sulphur

et al. 2019

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In this study, a new synthesis method was developed for the production of modified sol‐gel alumina (SG‐M) for the selective oxidation of H2S to elemental sulphur. The catalytic activity of this modified alumina without any active metal incorporation was then compared with the activity of commercial alumina (alumina‐com) for H2S selective oxidation. The N2 adsorption‐desorption isotherm showed that the SG‐M alumina synthesized in this work has a mesoporous structure with well‐defined hysteresis loops. Both alumina materials showed a γ‐Al2O3 crystalline phase with an amorphous structure in their crystal structure. The surface acidity of the alumina materials was determined using pyridine‐adsorbed FTIR analyses, and both alumina showed Lewis acid sites on their surfaces. The catalytic activity tests were performed at 250°C using a feed ratio of O2/H2S:0.5. The complete conversion of H2S over SG‐M was achieved during 400 minutes of reaction time. However, the commercial alumina lost its activity at earlier reaction times. Lewis acid sites and surface hydroxyl groups caused the alumina to be active in H2S selective catalytic oxidation, and the formation of Al‐S bonds, observed when the H2S conversion fell, caused a decrease in the catalytic activity of the alumina materials. A high sulphur yield (≥95%) was obtained over SG‐M, even though there was no active metal incorporation and even in the presence of excess oxygen. Considering the catalytic activities, the new sol‐gel alumina synthesized in this work is superior to commercial alumina. It was concluded that, as a catalyst without any active metal, SG‐M is a promising catalyst in H2S selective oxidation to sulphur.

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Effect of χ-alumina addition on H 2 S oxidation properties of pure and modified γ-alumina

Cited by 14 publications

References 73 publications

Effect of the Addition of Alkaline Earth and Lanthanide Metals for the Modification of the Alumina Support in Ni and Ru Catalysts in CO2 Methanation

Effect of the Addition of Alkaline Earth and Lanthanide Metals for the Modification of the Alumina Support in Ni and Ru Catalysts in CO2 Methanation

Ballistic Composites, the Present and the Future

A new sol‐gel route alumina for selective oxidation of H₂S to sulphur

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Effect of χ-alumina addition on H 2 S oxidation properties of pure and modified γ-alumina

Cited by 14 publications

References 73 publications

Effect of the Addition of Alkaline Earth and Lanthanide Metals for the Modification of the Alumina Support in Ni and Ru Catalysts in CO2 Methanation

Effect of the Addition of Alkaline Earth and Lanthanide Metals for the Modification of the Alumina Support in Ni and Ru Catalysts in CO2 Methanation

Ballistic Composites, the Present and the Future

A new sol‐gel route alumina for selective oxidation of H2S to sulphur

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Product

Resources

About

A new sol‐gel route alumina for selective oxidation of H₂S to sulphur